SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192e442a85d87f158db3b2484d804f8f13f67de316963ba192f2065b34852092' 
  AND token = 'MCghavUsVtunVUwL8bWD+xuWHCG4qqjGCxRZNC+b8pU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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