SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cdfa431f6f893bf8ebde6ff3234ead0a78c3ae6c826d1416e2cc33662ecd12cd' 
  AND token = 'qAvhX8U2ue1XcM63QBm63nXzI3aVFTRkePMhYChUKaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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