SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f3abad629ba3b065258c6055bed7b73f12d5c84b7cb3845ff06e9b6a68a40480' 
  AND token = 'gC/LMPEqSnjvrF4PuCgaYh1iVGVPDREf9FYqxnZYCBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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