SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f10cdbd791d67cb4b57337b29e5941dbb117b2a953ab7e514d7a4cfa794420bc' 
  AND token = 'WsgAEm2SfzhqxjYmJ3JPqspzPX82euKKenEeXjyGD1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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