SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11d5c28997557590b7905d0617350cc8ed231f7392fb0844fba3838ccfa3abc' 
  AND token = 'i7/KsY6CjRdJWonhSHKDvmHCNTLdvKqjbRSfe+ve4+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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