SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5959ebaad2e3836eb93189a90ea8ec68a808fc1c4088e750500a311495f3c58' 
  AND token = 'f0qJgFMETv+wRyoyrjLPCsT7VvOdb6OAolKNLSKZPX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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