SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2eabf8295b9daa465155714f520acda672d571db67daeb97fdff79eafbc59029' 
  AND token = 'AJ4oOD+X5lh09/Eu3TasDTH4zdqNtfhklsR62k6HTjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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