SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b264b9f206aec3eb01c260fef0124a1e85c9673370969617606d830628ab3970' 
  AND token = 'a5vdAKp/AbIItJ9WF2oopTxLRwnCigAigsinocGUruE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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