SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6943df4e70603e676a268c6bf30bbe495197b6a4df1d8cd1e54770765272a5a4' 
  AND token = 'YvqO8QFkMHCFRfxaw11ovVOp8+CpCVP66dUmZO/veDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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