SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e21cb228ee7c1601eec1c3269151fed475af02b10c2c64ec5bc10a3015e139a0' 
  AND token = 'pmrZBS9BIMVUaTyBtnBRGJoLb5f/a96gUyzaceFbl9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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