SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cdf6dbbd3da1e4685129e6478fea08935c506c1d01860b412237665823b0d0b' 
  AND token = 'ZQm/8lVhjDw5aMi6MzmR4Zq0Vt4fbkFPEXUsfZERyxg=' 
  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"
    }
  }
}