SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b3abcbe380f5db4fcbe2f6bb293e9ceacc8b4e706d75e042a9ed237b1f0c0c9' 
  AND token = 'iayZyyoe2aS808qzFd8CFw1ENJ71j1/Z6UPHBWEbq6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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