SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6361b00546e10878bfb90cd5b4145cd5bdea9cb9c99e201c625178b2a572680' 
  AND token = 'Ktb4NwdWPGKltlTObyXqqWTrrbMNduTtyk0BiT71N/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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