SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61d7a099d98eb36c87eda89ba17c1f35510669af1e5c0c82998bd674024e042' 
  AND token = 'CnqwtnqE3obYJEEBRFYGrTS4JdvlMTAT0M+WdSUi8H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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