SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0826f8b6015bd2760aee66b52878c6a3c138a504e7031077c9d35bf882055e1' 
  AND token = 'jVkPTwHxU7vG0gNcTlb7S2mbEgEhaMRD6PeUJ9k9+yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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