SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62159d41823360949eef90da2b39f0cc0d13c56bd5f60594c81ffdd2973a371c' 
  AND token = 'njHIh8ofLueaESguqVcW3gMsG33LaVC1mqxp+pnAILU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}