SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e581e07546d34f4d278ae4f1f2c55c1157e5bab07195d7c44f03a49550fd46af' 
  AND token = 'rnl1i6TRsWxKtwaylJb+gKAwqUkPJyoJlzx0QuRwBZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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