SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c0d59c3e6dac9507f2ac002556569df28ae93b5874dfdc0d9334f6a2e9a9d00' 
  AND token = 'NNuEFGfqsa+IZ6agJk7/LoyPJHIz8VZIhHKQObvYfqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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