SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a53f94efd4dc4c32857427594f63bb0ed78d1ba060ab3eaabdf1a8d75dbc4211' 
  AND token = 'CmDNN0q2RYJir0ejRBWXO7b7oS7R0sVVrifU621dmSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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