SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0fdea4fee2eddbd5d1ae150af4a9b20ef447401da8a55ef0f6b72344251f695' 
  AND token = 'v+CdVkIXSoD++lrWfrlxwrQUQ2gmj4vnU/OCaSOIsEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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