SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a288ae2d5768b3465b2372f64c324e4f6685d4a554abb2da1a0beb34cf12f096' 
  AND token = 'BDeoSO8EtVBxySU8XQYl022+TWZNNFa+rPTW0toJyyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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