SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a27c07ef45ef86c077357f4e120386bcdb44b9014e031ed41221a8e8bbe90fd1' 
  AND token = 'kRRiyCRwajn7MuBIDvvq+4LbQBUSmoA1s2ThE9QABMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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