SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b5e3ecde64bca58eaad753c367c91f421a615a09d3b35c2a7a047d918bb05be' 
  AND token = '4OYM9sll6zalT2UzV2Dvr5nBe4zZySzmHfRGsAMlGuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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