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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5675b5fe5303870e68df761b3bb8776fe1fc936073dba3d0bd09a99bcfe1d4a' 
  AND token = 'a/IR+xenrkPf/RkmiepPZGfAdJ/LBSMcpc5VuYA/OPk=' 
  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"
    }
  }
}