SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'de8334907614f62015c31fb868443b2d0229ba3937866066e44cf960f3b6550c' 
  AND token = '4zBJsjZyd/G+KMg2ksL9mI4PKfQV1Ngh6GWYfjYjQII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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