SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '505b891212a909194246d7b4bdd117339f9a2651a1983566a2fd0e35a3f430d1' 
  AND token = 'dGT8tIorut+Af1RKPWI+5d4Bwc1LHft1xlqwHpRlZnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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