SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b9dbae77ad48aef57e1ec32ae16ad8cd0f404910060351e4ea0b955079242c9b' 
  AND token = '1T2S9+ZcBpFfPFxQ/f9Gh5mkl0EsmCsM62AhVqfvpGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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