SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a6abca5dcce0612eadd783325c89be56d9ee77e0914be1aa063b1bb28b71ccf' 
  AND token = 'BbkW5WUfI3PaCimN4XGtAEnzWKBAaRS9NNaaafjFV00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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