SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7a6c8562f95587c20668dad19fceba05a14f6f5c116af84f01344af58c9910fb' 
  AND token = 'rrazWF3+edJxG+Xebb6expimXieNekMkIGoLvlzGW2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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