SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad1f4605c0571f972a25d10959a932e4d234ff1263d1ff6702558887e02b4ca' 
  AND token = 'f2VmGqSc9kJqf0ShOtacgFbSIqzq1gL9wujv+P8dY5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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