SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3466f460eefaa235200974185e6b74b1879858656d0f8d9b817d5c5ae83b03f6' 
  AND token = 'MtwbYvj33qRhVSgpBPGKyGAipAzle+bKb0/XiHPeUYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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