SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c1849d6589a7709278b6ad6ce68e31ea44cd84213ded02fa577201a710263f1' 
  AND token = 'b3LqYIAO/GbxPv3wuToR3JYIifWrITwQwZt3oEC+RA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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