SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a2504ae502810ef33d1ee4d50ef0d34c6ea13efcb6187087334bd4574937dd3' 
  AND token = 'COjTuS8ykjp8qSWGJhvcfKtOONXxmPHOwsCHl3F7uho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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