SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b44188621ecd6aea21100ad10b84ffe6c593dac6b48dc4b20276dd7d1dd1c270' 
  AND token = 'pnyGxB0JoqdwFHsx6uOQeRmvYl3siviC6M0aTg55hg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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