SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c92f58bf4280398b090293496415d1eec7534d726201f337c4ec4e32c1b835' 
  AND token = 'DyrBFpXsS59cqyFaRprQbE2s4M5VSFqLLiDh2U9M4Ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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