SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40fb49fbb9ea96f32c7de3d6198a9b837fb6cda7203932752227a0f43c5a0d76' 
  AND token = '+RD1705tIf8ethqKeZ8SVKToQbjk7jl038nKLhUFgzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}