SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5b150090f50ca56827e3ebf70a5e9c073efbbd5d34e9994acadb851a77fd4d3' 
  AND token = 'j+Oin+BRWezOuYWVZkqlSlu3MaehALlM4rey7SPQNLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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