SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8a4d5b20b3c791388aef207ab861edab29636d92a1b8f5bd034a4b1db34927fe' 
  AND token = '3k+CPNnIk95M0Oe5phaX90iVMp9rWSzq3+irmjhCIAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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