SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cf3f7516e9e1b2806356e79f5148d2c925a719427178650a7f156c6fb57118a' 
  AND token = 'DmpR4vZj7L6ABSI0aKKkMUr62hypigZFuL6i5+X5jp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}