SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62b6a7b5ffcba136a9f7b6ad704b34a2d821e05295697512e1008c597ea2a47a' 
  AND token = 'IDYZFPKW5d9JZBAetagwU0xq4IBg/0wAvS3zGEneJb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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