SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '757cf09e0df399076d23691fc1aecaa85a35ef87bc8c5b3ef1943a146804921a' 
  AND token = 'sYLzUkECNw8+TM3X6qMO0Dj2Nc//7wpjuvpgteV527U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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