SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7823e349212c324aefe0c38d87d7aaff03389eb3d2dfd21d35ec753312fac119' 
  AND token = 'yvhX+808gpI3oXovVUfvAXl7JJQtd1ntSoNxE91fozo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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