SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8267b31acf8df46e9bbce085729260fbeab66e9e6a9153613863ce73e7485fd' 
  AND token = 'P+Of9yguwn64Cte8UopjywXogr1OrIsEkU2DWYurGf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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