SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'bf2d8d548263bd7d6900391deb4d6f15b0d5e0e767097cabf8d0c81eeb2b5141' 
  AND token = 'kJ55VodeolbysThCt1PUJjM7T2mZVgBRRWdBNPurPbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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