SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6d26099143bfbfa8918b9cd6d497a974e29e0dd192763e8194c1686e4c22b11' 
  AND token = '/7NtnkYs7BHslyLbmF3Bf2efmKZ5uJ0zjGm2v2wAsXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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