SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59f537cd2700459c76cbdc57c273befee4175fef85a2e6abb2996942a93e8034' 
  AND token = 'RAtXJvsKOS5Lbu6J09VupdwEKhQ/HFn/Ktj2+LQRJAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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