SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31bcf3a33e5d9ac6d26420f025ccca18150b6fb38d5ddc443b9466424826c2ef' 
  AND token = 'jze9QQkZTmRd0rdPk57upNe29HFRYcLCekPY5XrKGlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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