SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d3cb9b35344efc666e9f9ee81dc346e7652ae0d37048d3e49461e4a5a7cd893' 
  AND token = 'Jq5ffzzwA6zJW7+hsRUKPwvmtHhXOeCHRdOWcp+qcjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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