SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4046575111cd8ac36521c25ef6e9c66fecdcbff65216a911ed7a7a66ddf58c3' 
  AND token = '7i/5JbyLcYqD6ogtk6sHNZnt8NiBh60XofsP9rjCwdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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