SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd7f345d2eb93288b8f0bb141fddda319c6b7433bb760251251962c529d10712' 
  AND token = 'P1zX1yB70y6pYrWIfJ7XqEFP9lMUB3eg+R0ZMGIVPFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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