SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '418928d6108c64140c2aac4624ffb189e3f37f3e5f64e2f358c2ec66c4a0f868' 
  AND token = '+jlGvdS1CTCllM/pgZr5WgXwVysFqauaY21cPmm7RIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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