SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f423c55d44317054c7c0e805bfe053e2499c2196f713ef52b02f6699514b5cbb' 
  AND token = 'n85aIlEqUpHoYgj+KnEe/Tee31DU0F81o3d5g7wPHFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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