SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8da74f27411804639b794072af7fc073bad85600372883cab7500ad6d4b66e03' 
  AND token = 'CMnoxPcxImjV0X8I3I/huZTDMifaBiYZQNzCUctB9Ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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