SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfcb64fd56421937b1ef29d9178896ef957025633d8285da96eb7b4a87497014' 
  AND token = 'iyN7VQr14RdO+I3L9s7S6iMABTyQVwJINtqkNFxY01w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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