SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30e338aec4833d286b26c06a2401649779a4d61e37775d84d23ce0230ebe3866' 
  AND token = 'SDWOy2wSSwN8eXTgmLJoXf8JZEpG1avQB4VmfbuTZkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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