SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef612b0925822ff1183a13a799b6f38dd4b52c45b10fca4af616c1c4c27385d1' 
  AND token = 'fIZykmoRq3voGXtUFQB3LACiLw2Ry/ouPeS2D7V04kY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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