SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f963811d3151fffb15cabcb403e89e3b9bc2f974e72adfd42c993b59b9d68b1d' 
  AND token = 'cpFuQKVDL80qXF4gR0vdobDAGjasjG66DNVa+B08n+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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